Proceedings of the Royal Society B: Biological Sciences, 2023
It is unclear whether our brain extracts and processes time information using a single-centralize... more It is unclear whether our brain extracts and processes time information using a single-centralized mechanism or through a network of distributed mechanisms, which are specific for modality and time range. Visual adaptation has previously been used to investigate the mechanisms underlying time perception for millisecond intervals. Here, we investigated whether a well-known duration after-effect induced by motion adaptation in the sub-second range (referred to as 'perceptual timing') also occurs in the supra-second range (called 'interval timing'), which is more accessible to cognitive control. Participants judged the relative duration of two intervals after spatially localized adaptation to drifting motion. Adaptation substantially compressed the apparent duration of a 600 ms stimulus in the adapted location, whereas it had a much weaker effect on a 1200 ms interval. Discrimination thresholds after adaptation improved slightly relative to baseline, implying that the duration effect cannot be ascribed to changes in attention or to noisier estimates. A novel computational model of duration perception can explain both these results and the bidirectional shifts of perceived duration after adaptation reported in other studies. We suggest that we can use adaptation to visual motion as a tool to investigate the mechanisms underlying time perception at different time scales.
Proceedings of the Royal Society B: Biological Sciences, 2023
It is unclear whether our brain extracts and processes time information using a single-centralize... more It is unclear whether our brain extracts and processes time information using a single-centralized mechanism or through a network of distributed mechanisms, which are specific for modality and time range. Visual adaptation has previously been used to investigate the mechanisms underlying time perception for millisecond intervals. Here, we investigated whether a well-known duration after-effect induced by motion adaptation in the sub-second range (referred to as 'perceptual timing') also occurs in the supra-second range (called 'interval timing'), which is more accessible to cognitive control. Participants judged the relative duration of two intervals after spatially localized adaptation to drifting motion. Adaptation substantially compressed the apparent duration of a 600 ms stimulus in the adapted location, whereas it had a much weaker effect on a 1200 ms interval. Discrimination thresholds after adaptation improved slightly relative to baseline, implying that the duration effect cannot be ascribed to changes in attention or to noisier estimates. A novel computational model of duration perception can explain both these results and the bidirectional shifts of perceived duration after adaptation reported in other studies. We suggest that we can use adaptation to visual motion as a tool to investigate the mechanisms underlying time perception at different time scales.
Our ability to estimate the duration of sub-second visual events is prone to distortions, which d... more Our ability to estimate the duration of sub-second visual events is prone to distortions, which depend both on sensory and decisional factors. To disambiguate between these two influences, we can look at the alignment between discrimination estimates of duration at the point of subjective equality and confidence estimates when the confidence about decisions is minimal, because observers should be maximally uncertain when two stimuli are perceptually the same. Here, we used this approach to investigate the relationship between the speed of a visual stimulus and its perceived duration. Participants were required to compare two intervals, report which had the longer duration, and then rate their confidence in that judgement. One of the intervals contained a stimulus drifting at a constant speed, whereas the stimulus embedded in the other interval could be stationary, linearly accelerating or decelerating or drifting at the same speed. Discrimination estimates revealed duration compress...
Duration distortions have been shown to occur at the time of saccades and following high temporal... more Duration distortions have been shown to occur at the time of saccades and following high temporal frequency or contrast adaptation. Under all these conditions, changes in the temporal tuning of M neurons also occur, suggesting that there might be a link between the two phenomena. In order to explore this relationship further, we measured the apparent duration of visual stimuli in the dark, where the temporal impulse response has been reported to lengthen. We first measured a progressive shift and reduction of the occurrence of an apparent motion reversal as we decreased the luminance level, indicating a lengthening of the temporal impulse response. We then measured perceived duration at these luminance levels (0.75, 3, and 50 cd/m) after matching for apparent contrast and temporal frequency. While perceived temporal frequency did not substantially differ across luminance levels, duration appeared expanded at the lowest luminance level relative to the highest by approximately 60 ms. ...
The brain combines sounds from the two ears, but what is the algorithm used to achieve this fusio... more The brain combines sounds from the two ears, but what is the algorithm used to achieve this fusion of signals? Here we take a model-driven approach to interpret both psychophysical increment detection thresholds and steady-state electrophysiology (EEG) data to reveal the architecture of binaural combination for amplitude modulated tones. Increment thresholds followed a ‘dipper’ shaped function of pedestal modulation depth, and were consistently lower for binaural than monaural presentation. The EEG responses were greater for binaural than monaural presentation, and when a modulated masker was presented to one ear, it produced only weak suppression of the signal presented to the other ear. Both data sets were well-fit by a computational model originally derived for visual signal combination, but with suppression between the two channels (ears) being much weaker than in binocular vision. We suggest that the distinct ecological constraints on vision and hearing can explain this differe...
The ability of subjects to identify and reproduce brief temporal intervals is influenced by many ... more The ability of subjects to identify and reproduce brief temporal intervals is influenced by many factors whether they be stimulus-based, task-based or subject-based. The current study examines the role individual differences play in subsecond and suprasecond timing judgments, using the schizoptypy personality scale as a test-case approach for quantifying a broad range of individual differences. In two experiments, 129 (Experiment 1) and 141 (Experiment 2) subjects completed the O-LIFE personality questionnaire prior to performing a modified temporal-bisection task. In the bisection task, subjects responded to two identical instantiations of a luminance grating presented in a 4deg window, 4deg above fixation for 1.5 s (Experiment 1) or 3 s (Experiment 2). Subjects initiated presentation with a button-press, and released the button when they considered the stimulus to be half-way through (750/1500 ms). Subjects were then asked to indicate their 'most accurate estimate' of the ...
Adapting to a 20 Hz oscillating grating reduces the apparent duration of a 10 Hz drifting grating... more Adapting to a 20 Hz oscillating grating reduces the apparent duration of a 10 Hz drifting grating displayed subsequently in the same location as the adaptor. The effect is orientation-independent as it remains once the adaptor is rotated 90° relative to the tests (Johnston, Arnold, & Nishida, 2006). However, it was shown that, for random dots moving at 3°/s, duration compression follows adaptation only when the adaptor and test drift in the same direction, and it disappears when they drift in opposite directions (Curran & Benton, 2012). Here, we explored the relationship between the relative motion direction of adaptor and test and the strength of duration compression for a wider range of speeds and for narrow-band stimuli (temporal frequencies between 3 and 18 Hz). We first measured perceived temporal frequency for the same stimuli after adaptation, and we used these estimates to match the apparent rate of the adapted and unadapted tests in the duration task. We found that, whereas...
Attention has been shown to modulate visual processing in a wide variety of tasks. We tested the ... more Attention has been shown to modulate visual processing in a wide variety of tasks. We tested the influence of attention on the temporal integration of motion for both central and peripherally viewed targets (6 degrees x 6 degrees ). Consistent with previous results, motion sensitivity for a brief motion signal (70-3500 ms) embedded in noise (10 s) increased as a function of motion duration up to a critical duration of about 1.5 s. Summation times for centrally and peripherally viewed targets were similar. An effect of eccentricity was found, however, in a double-motion task, in which two brief (150 ms) motion signals were presented with varying delays (0-7 s) of random noise between the two signals. Specifically, the maximum delay between the two signals that still supported temporal summation (summation constant) was about three times longer for centrally viewed targets (3.5-4.5 s versus 1.5-2 s). We investigated the role of spatial attention in the double-motion task by adding a c...
Adapting to a 20 Hz drifting grating compresses perceived duration for 10Hz stimuli displayed in ... more Adapting to a 20 Hz drifting grating compresses perceived duration for 10Hz stimuli displayed in the adapted location (Johnston, Arnold & Nishida, 2006, Current Biology, 16(5):4729). However, Burr, Tozzi & Morrone (2007, Nature Neuroscience, 10(4): 4235) described ...
Proceedings of the Royal Society B: Biological Sciences, 2023
It is unclear whether our brain extracts and processes time information using a single-centralize... more It is unclear whether our brain extracts and processes time information using a single-centralized mechanism or through a network of distributed mechanisms, which are specific for modality and time range. Visual adaptation has previously been used to investigate the mechanisms underlying time perception for millisecond intervals. Here, we investigated whether a well-known duration after-effect induced by motion adaptation in the sub-second range (referred to as 'perceptual timing') also occurs in the supra-second range (called 'interval timing'), which is more accessible to cognitive control. Participants judged the relative duration of two intervals after spatially localized adaptation to drifting motion. Adaptation substantially compressed the apparent duration of a 600 ms stimulus in the adapted location, whereas it had a much weaker effect on a 1200 ms interval. Discrimination thresholds after adaptation improved slightly relative to baseline, implying that the duration effect cannot be ascribed to changes in attention or to noisier estimates. A novel computational model of duration perception can explain both these results and the bidirectional shifts of perceived duration after adaptation reported in other studies. We suggest that we can use adaptation to visual motion as a tool to investigate the mechanisms underlying time perception at different time scales.
Proceedings of the Royal Society B: Biological Sciences, 2023
It is unclear whether our brain extracts and processes time information using a single-centralize... more It is unclear whether our brain extracts and processes time information using a single-centralized mechanism or through a network of distributed mechanisms, which are specific for modality and time range. Visual adaptation has previously been used to investigate the mechanisms underlying time perception for millisecond intervals. Here, we investigated whether a well-known duration after-effect induced by motion adaptation in the sub-second range (referred to as 'perceptual timing') also occurs in the supra-second range (called 'interval timing'), which is more accessible to cognitive control. Participants judged the relative duration of two intervals after spatially localized adaptation to drifting motion. Adaptation substantially compressed the apparent duration of a 600 ms stimulus in the adapted location, whereas it had a much weaker effect on a 1200 ms interval. Discrimination thresholds after adaptation improved slightly relative to baseline, implying that the duration effect cannot be ascribed to changes in attention or to noisier estimates. A novel computational model of duration perception can explain both these results and the bidirectional shifts of perceived duration after adaptation reported in other studies. We suggest that we can use adaptation to visual motion as a tool to investigate the mechanisms underlying time perception at different time scales.
Our ability to estimate the duration of sub-second visual events is prone to distortions, which d... more Our ability to estimate the duration of sub-second visual events is prone to distortions, which depend both on sensory and decisional factors. To disambiguate between these two influences, we can look at the alignment between discrimination estimates of duration at the point of subjective equality and confidence estimates when the confidence about decisions is minimal, because observers should be maximally uncertain when two stimuli are perceptually the same. Here, we used this approach to investigate the relationship between the speed of a visual stimulus and its perceived duration. Participants were required to compare two intervals, report which had the longer duration, and then rate their confidence in that judgement. One of the intervals contained a stimulus drifting at a constant speed, whereas the stimulus embedded in the other interval could be stationary, linearly accelerating or decelerating or drifting at the same speed. Discrimination estimates revealed duration compress...
Duration distortions have been shown to occur at the time of saccades and following high temporal... more Duration distortions have been shown to occur at the time of saccades and following high temporal frequency or contrast adaptation. Under all these conditions, changes in the temporal tuning of M neurons also occur, suggesting that there might be a link between the two phenomena. In order to explore this relationship further, we measured the apparent duration of visual stimuli in the dark, where the temporal impulse response has been reported to lengthen. We first measured a progressive shift and reduction of the occurrence of an apparent motion reversal as we decreased the luminance level, indicating a lengthening of the temporal impulse response. We then measured perceived duration at these luminance levels (0.75, 3, and 50 cd/m) after matching for apparent contrast and temporal frequency. While perceived temporal frequency did not substantially differ across luminance levels, duration appeared expanded at the lowest luminance level relative to the highest by approximately 60 ms. ...
The brain combines sounds from the two ears, but what is the algorithm used to achieve this fusio... more The brain combines sounds from the two ears, but what is the algorithm used to achieve this fusion of signals? Here we take a model-driven approach to interpret both psychophysical increment detection thresholds and steady-state electrophysiology (EEG) data to reveal the architecture of binaural combination for amplitude modulated tones. Increment thresholds followed a ‘dipper’ shaped function of pedestal modulation depth, and were consistently lower for binaural than monaural presentation. The EEG responses were greater for binaural than monaural presentation, and when a modulated masker was presented to one ear, it produced only weak suppression of the signal presented to the other ear. Both data sets were well-fit by a computational model originally derived for visual signal combination, but with suppression between the two channels (ears) being much weaker than in binocular vision. We suggest that the distinct ecological constraints on vision and hearing can explain this differe...
The ability of subjects to identify and reproduce brief temporal intervals is influenced by many ... more The ability of subjects to identify and reproduce brief temporal intervals is influenced by many factors whether they be stimulus-based, task-based or subject-based. The current study examines the role individual differences play in subsecond and suprasecond timing judgments, using the schizoptypy personality scale as a test-case approach for quantifying a broad range of individual differences. In two experiments, 129 (Experiment 1) and 141 (Experiment 2) subjects completed the O-LIFE personality questionnaire prior to performing a modified temporal-bisection task. In the bisection task, subjects responded to two identical instantiations of a luminance grating presented in a 4deg window, 4deg above fixation for 1.5 s (Experiment 1) or 3 s (Experiment 2). Subjects initiated presentation with a button-press, and released the button when they considered the stimulus to be half-way through (750/1500 ms). Subjects were then asked to indicate their 'most accurate estimate' of the ...
Adapting to a 20 Hz oscillating grating reduces the apparent duration of a 10 Hz drifting grating... more Adapting to a 20 Hz oscillating grating reduces the apparent duration of a 10 Hz drifting grating displayed subsequently in the same location as the adaptor. The effect is orientation-independent as it remains once the adaptor is rotated 90° relative to the tests (Johnston, Arnold, & Nishida, 2006). However, it was shown that, for random dots moving at 3°/s, duration compression follows adaptation only when the adaptor and test drift in the same direction, and it disappears when they drift in opposite directions (Curran & Benton, 2012). Here, we explored the relationship between the relative motion direction of adaptor and test and the strength of duration compression for a wider range of speeds and for narrow-band stimuli (temporal frequencies between 3 and 18 Hz). We first measured perceived temporal frequency for the same stimuli after adaptation, and we used these estimates to match the apparent rate of the adapted and unadapted tests in the duration task. We found that, whereas...
Attention has been shown to modulate visual processing in a wide variety of tasks. We tested the ... more Attention has been shown to modulate visual processing in a wide variety of tasks. We tested the influence of attention on the temporal integration of motion for both central and peripherally viewed targets (6 degrees x 6 degrees ). Consistent with previous results, motion sensitivity for a brief motion signal (70-3500 ms) embedded in noise (10 s) increased as a function of motion duration up to a critical duration of about 1.5 s. Summation times for centrally and peripherally viewed targets were similar. An effect of eccentricity was found, however, in a double-motion task, in which two brief (150 ms) motion signals were presented with varying delays (0-7 s) of random noise between the two signals. Specifically, the maximum delay between the two signals that still supported temporal summation (summation constant) was about three times longer for centrally viewed targets (3.5-4.5 s versus 1.5-2 s). We investigated the role of spatial attention in the double-motion task by adding a c...
Adapting to a 20 Hz drifting grating compresses perceived duration for 10Hz stimuli displayed in ... more Adapting to a 20 Hz drifting grating compresses perceived duration for 10Hz stimuli displayed in the adapted location (Johnston, Arnold & Nishida, 2006, Current Biology, 16(5):4729). However, Burr, Tozzi & Morrone (2007, Nature Neuroscience, 10(4): 4235) described ...
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